Heat recovery apparatus and method for molding

ABSTRACT

Method for recapturing and reusing heat provided in the course of fabricating a molded plastic product.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a 35 USC 120 division of co-pending U.S.patent application Ser. No. 14/164,663 filed 27 Jan. 2014 in the name ofStephen B. Maguire and entitled “Molding Apparatus and Method with HeatRecovery”

The '663 application is a 35 USC 120 continuation of U.S. patentapplication Ser. No. 12/350,455 filed 8 Jan. 2009 in the name of StephenB. Maguire and entitled “Molding Apparatus and Method with HeatRecover”; the '455 application has been abandoned.

This patent application claims the benefit of the priority of the '663application and the priority of the '455 application through the '663application pursuant to 35 USC 120.

FIELD OF THE INVENTION

This invention relates to apparatus and methods for recovering heat froma molded product and/or the machine in which the product is molded andapplying the recovered heat to resin prior to molding. Morespecifically, this invention conserves energy by recirculating heatcaptured from the molded product and/or the molding machine to pre-heatthe raw resin molding material, before the raw resin material enters anextruder or a molding apparatus.

BACKGROUND OF THE INVENTION

Molded products, such as plastics, and the like, have been known fordecades and are used, inter alia, for product packaging, productpresentation, material storage, and the like. Because of theirwidely-varying nature and characteristics, energy efficient methods ofproducing these items are a necessity. Of particular interest aremethods to quickly cool a molded product, particularly within thecontext of manufacturing facilities.

Previous methods of cooling, while effective in cooling a product ofinterest, are wasteful in failing to recapture heat lost duringprocessing. Rather than being reused, the heat was entirely lost, thusincreasing energy costs by requiring more heat in earlier processingsteps. Known systems and methods are largely inefficient, therebyincreasing operating costs of molding and manufacturing molded products.

Early cooling methods included the application of either ambient airfrom a fan or compressed air blown across the molded product immediatelyafter molding. These convective cooling methods removed heat from themolded product. The removed heat, however, was not contained within aclosed system, but was wastefully lost. Thus, while the molding methodachieved its objective, it was largely inefficient, as additional energywas required to create the required heat in earlier processing steps.

U.S. Pat. No. 4,657,574 discloses cooling molded glass using arod-shaped material of higher thermal conductivity than the mold.Specifically, the rod-shaped material extends through the mold in aposition proximate to the heated product, where the rod is able toextract heat from the heated product and then withdraw into a recess.This apparatus and method are largely inefficient because the heatextracted from the resulting product is not reused within the system butis lost.

U.S. Pat. Nos. 4,313,751; 5,398,745; 5,824,237; and 7,303,387 disclosealternative methods of cooling a molded product using convective fluidflow. Specifically, each of these patents discloses a molding machinewith one or more channels passing through the mold, proximate to theheated product. A cooling medium, e.g. water, may be passed throughthese channels and, ultimately, through the mold itself. As it passesthrough the mold, the cooling medium extracts heat from the moldedproduct that is in the mold using convective cooling mechanisms. Whilethese approaches appropriately cool the heated product, they do not usethe extracted heat in any way. Rather, the heat is largely lost,providing inefficiency within the system.

U.S. Pat. No. 3,748,866 discloses an alternative wherein a heatedproduct is cooled using a larger refrigeration system. A first loop ofcirculated cooling fluid passes through channels of the mold and througha heat exchanger. As the fluid of the first loop passes through themold, the fluid receives heat, thereby cooling the molded product. Theheated fluid then passes into a heat exchanger in which fluid from asecond coolant loop extracts the heat from the first loop. The fluidfrom the first loop is then recirculated back through the mold and thefluid from the second loop is provided to a compressor and an associatedcondenser, where it is cooled and recirculated to the heat exchanger.While this system uses multiple processing steps to provide acirculation system for lowering the temperature of the mold, there is noreapplication of the captured heat back to the molding process. Thus,this system does not maximize efficiency of a molding method.

Based on the foregoing, apparatus and methods for cooling a moldedproduct with little to no loss of the recaptured heat are desirable.Apparatus and methods are further desirable that recapture heat from themolded product and apply that heat to one or more earlier steps in themolding process. Finally, apparatus and methods are desirable forextracting heat from the molded product and reapplying that heat toun-molded resin such that the resin is heated prior to being molded.

This invention addresses these needs.

SUMMARY OF THE INVENTION

This invention relates to molding apparatus and methods for recapturingand reusing heat from a molded product. More specifically, thisinvention provides apparatus and methods for recapturing heat from amolded product and circulating the heat to raw material, namely resin,to facilitate heating the raw material, to at least warm it prior tomolding. Accordingly, this invention provides apparatus and methods forconserving energy in molding processes, making these processes moreenergy and cost efficient.

In one of its manifestations, the apparatus and methods of thisinvention include a molding press, a heat exchanger, a raw materialcontainer, and one or more fluid channels providing thermal connectionamong these elements. The fluid channels may be in the form of acontinuous loop between the molding press and the heat exchanger whereheat from the molded product in the molding press is transferred to theheat exchanger by first fluid flow within these channels. The fluidchannels establish a convective flow between the molding press and theheat exchanger such that heat from a molded product and the proximateportion of the molding press is transferred from the molding press tothe heat exchanger.

Heat directed into the heat exchanger is then preferably transferred toa second fluid medium such that the first fluid is cooled and the secondfluid is heated. The cooled first fluid is then preferably recirculatedback to the molding press and the heated second fluid is preferablyredirected into a container housing raw material to be molded,preferably plastic resin. Within this container, heat from the secondfluid is absorbed by the materials to be molded, thereby heating thematerials to be molded and cooling the second fluid, which is thenevacuated from the container into either the surrounding environment orback into the heat exchanger. To this end, the apparatus and methods ofthis invention provide a circulation system adapted to extract heat fromthe molded product produced by the molding press and to apply this heatto raw material that is awaiting molding in the container.

In a preferred embodiment, the first fluid is water, which is circulatedthrough the molding press and heat exchanger via one or more channels.In the molding press, the water absorbs heat from the molded product andthe surrounding part of the molding press, resulting in an increase inthe temperature of the water and cooling of the molded product. Theheated water then flows into the heat exchanger.

In the heat exchanger, ambient air is preferably directed along and/oracross the fluid channels housing the water, thereby extracting heatfrom the water. As the heat is extracted, the water is cooled and airflow is proportionately increased, resulting in transfer of heat fromone medium to the other. The heated air is then redirected into andthrough a container housing raw resin that is ready to be molded. As theair passes through the container, heat from the air is absorbed by theresin, thereby heating the resin and cooling the air. The cooled air isthen evacuated from the container and, optionally, recirculated back tothe heat exchanger.

In effect, this invention recovers heat coming from a molded productwithin the molding press and reuses this heat in an earlier processstep. This is advantageous because it provides cost and energyefficiency to the overall molding process.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front elevation of apparatus manifesting aspectsof the invention, illustrating in schematic form a generic moldingapparatus, a generic heat exchanger, and a raw material container, withfluid flow provided therebetween.

FIG. 2 is a schematic isometric view of the FIG. 1 molding apparatus,having a plurality of fluid flow channels passing therethrough.

FIGS. 3A through 3C are schematic isometric views of the genericshell-tube type heat exchanger depicted in FIG. 1, having a first fluidflow channel passing therethrough and a flow path for a second fluidacross the first fluid flow channel. FIG. 3A depicts a parallel-flowshell-tube type heat exchanger; FIG. 3B depicts a counterflow shell-tubetype heat exchanger; and FIG. 3C depicts a cross-flow shell-tube typeheat exchanger.

FIG. 4A is a schematic depiction of laminar fluid flow; FIG. 4B is aschematic depiction of turbulent fluid flow.

FIG. 5 is a flow chart depicting process aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a molding apparatus, especially moldingpresses, and methods facilitating recapture and reuse of heat producedin the course of molding a product. More specifically, this inventionprovides apparatus and methods for recapturing heat produced in thecourse of fabricating a molded product and circulating the recapturedheat to raw material awaiting molding, to heat these materials prior tomolding them, thereby reducing the amount of heat required during theactual molding process. Accordingly, this invention provides apparatusand methods for conserving energy in molding processes, thereby makingthe processes more energy and cost efficient.

Referring to FIG. 1, a schematic, generic representation of apparatusmanifesting aspects of the invention is generally indicated by referencenumber 1. In this embodiment of the invention, the apparatus includes,at least, a molding apparatus, desirably a molding press, illustratedschematically as 5, a heat exchanger 10, a raw material container 65,and channels 15, 60, 70 for fluid flow. A first set of one or morechannels 15 provides a continuous loop between molding apparatus 5 andheat exchanger 10 wherein heat from a molded product produced withinmolding apparatus 5 is carried to heat exchanger 10 by fluid withinchannels 15. To this end, channels 15 pass through molding apparatus 5where a first fluid within channels 15 absorbs heat from the moldedproduct within apparatus 5 and from parts of apparatus 5 that areproximate to the molded product. This heated fluid then travels frommolding apparatus 5 in the direction of arrows A towards and into heatexchanger 10.

Within heat exchanger 10, heat stored within the first fluid istransferred to a second fluid such that the first fluid is cooled andthe second fluid is heated. While the cooled first fluid is recirculatedback to molding apparatus 5, the heated second fluid is then directedalong channel 70 towards and into raw material container 65. As thesecond fluid passes through container 65, heat from the second fluid isabsorbed by the raw material in container 65 resulting in overallheating of the raw material prior to processing. The second fluid iscooled as it passes through container 65 and gives up its heat to theraw material within container 65. The second fluid may be eitherevacuated to the surrounding environment or recirculated back towardsheat exchanger 10 by channel 60. To this end, in the schematicallyillustrated embodiment, the apparatus and method provide a dualcirculation system for extracting heat from the molded product producedby molding apparatus 5 and applying this heat to raw material withincontainer 65.

Referring to FIG. 2, a schematic representation of a molding apparatus 5is illustrated. Molding apparatus 5 is illustrated as including twohalves 20, 25, each having an interior surface 35 and an exteriorsurface 40. Most preferably, the interior surfaces 35 of each half 20,25 are aligned such that, when connected, the two halves 20, 25 defineone or more hollow chambers 30, typically referred to as “moldcavities”, therebetween. The hollow chamber(s) 30 are configured to forma molded product, which may be of any desirable shape or configuration,e.g. preforms, containers, or any other articles that are formed bycompression, injection or blow molding. The hollow chamber(s) 30, andmolding apparatus 5, may be adapted to receive any type of material thatis known in the art for molding. Such materials may include, but are notlimited to, glass, metals, plastics, ceramics, and the like. Thepreferred material is resin used to mold plastic products.

The molding halves, which define the mold, may be made of any materialknown in the art for use in a molding apparatus. For example, the moldmay be a steel alloy or cast iron halves that are held together usingany suitable means. Accordingly, the size, shape, composition, etc. ofthe molding apparatus is not limiting as respecting this invention.Rather, molding apparatus 5 as illustrated schematically may be any formor type of molding apparatus that is known in the art such as, but notlimited to, stretch blow-molding apparatus, injection molding apparatus,compression molding apparatus, thermomolding or thermoforming apparatus,vacuum forming apparatus, transfer molding apparatus, extrusionapparatus, rotational molding apparatus, and the like. The moldingapparatus 5 may include additional elements known in the art as beinguseful for molding such as, but not limited to, non-stick surfaces,specialty heat dissipating surfaces, and the like.

In any of the forgoing forms and embodiments, molding apparatus 5includes one or more fluid channel portions designated C where “C”denotes the fluid flow throughout portions of channels 15 that arewithin molding apparatus 5, facilitating cooling fluid flow through oraround molding apparatus 5 in positions adjacent to hollow cavity 30 soas to be thermally coupled thereto. As illustrated in FIG. 2, thechannels 15 may pass from one side of the exterior surface of a moldhalf, through the interior of the mold, and out an opposite side of theexterior surface of a mold half. Most preferably, the channels 15 passthrough or about the mold halves such that fluid within the channelsreceives heat that is conducted, convected and/or radiated from themolded product, with such heat flow being represented by arrows B ofFIG. 2. Heat flow through the unmarked structure that thermally coupleshollow mold cavity 30 to portion C of channel 15 is denoted by letter“B” in FIG. 2.

While FIG. 2 illustrates four such channels passing through the mold,the invention is not so limited. Rather, this invention may include moreor fewer channels, based on the desired and effective rates of coolingthe molded product. While channels 15 are illustrated in FIG. 2 aspassing directly through molding apparatus 5, this invention is notlimited to this configuration. Rather, the channel(s) may be rounded oradapted to substantially encircle the molded product one or multipletimes so as to increase the surface area exposed to recover heat fromthe molded product.

Channels 15 provide primarily convective cooling for lowering thetemperature of the molded product. To facilitate this objective,channels 15 may be formed from any suitable thermally conductivematerial, typically a high melting point metal. The thermally conductivechannels 15 may be the same material as molding apparatus 5 and/or maybe integrally formed therein and extend therefrom. Accordingly, channels15 may be comprised of bores machined through molding apparatus 5 thatare coupled to and in fluid communication with external portions of thechannels passing between molding apparatus 5 and heat exchanger 10, asshown in FIG. 1. In such an arrangement, it may also be desirable thatchannels 15 be comprised of a thermally conductive surface within themolding apparatus, but be insulated at the exterior portions extendingbetween molding apparatus 5 and heat exchanger 10. In such anembodiment, heat transferred into the channels 15 within the moldingapparatus is not lost when traveling along channel 15 to heat exchanger10. Such insulation may be provided by means exterior to these portionsof the channel 15, e.g. an insulative jacket, or by a variation in thecomposition of channel 15 at these positions, to provide such insulativeproperties.

Alternatively, the thermally conductive material of channels 15 may becomprised of different, preferably more conductive, materials thanmolding apparatus 5. In this approach, channels 15 may be configured asa continuous loop, where the channels pass through bores machined intomolding apparatus 5. Most preferably, bore diameter is essentially thesame as the exterior diameter of the channel such that the channels maybe easily coupled to the molding apparatus. Again, the portions of thechannel 15 not contained within molding apparatus 5 or heat exchanger 10should be insulated such that heat is not lost as the fluid travelstherebetween.

A cooling medium is conveyed through channels 15 to facilitateconvective extraction of heat from the molded product. This coolingmedium may be any suitable thermally conductive fluid. Such coolingfluids may include, but are not limited to, water, air, oil,refrigerant, and the like. Most preferably the cooling medium is water.As illustrated by arrows C in FIG. 2, flow of the thermally conductivefluid may provide a current of fluid passing very close to the hollowcavity(s) 30. The fluid flow may be laminar, as depicted in FIG. 4A,wherein fluid glides through the channel in smooth layers with theinnermost layer typically flowing at a higher rate than the outermostlayer. More preferably, however, the fluid flow is turbulent, asdepicted in FIG. 4B, wherein the flow is agitated rather than smooth.Turbulent flow is preferred because laminar flow tends to develop aninsulating blanket around the channel wall, thus reducing heat transfer.Turbulent flow, however, being agitated, thereby prevents any suchinsulating blanket from forming and allows a greater surface area of thefluid to conduct heat. To this end, the cooling medium turbulently flowsthrough the molding apparatus 5, extracting heat from the molded productwithin the hollow cavity(s) 30. This results in an increase in thetemperature of the cooling medium as it passes through the moldingapparatus 5 and a decrease in the temperature of the molded productwithin the hollow cavity(s) 30.

Fluid within channels 15 may be provided by a storage tank (notillustrated) or some alternative source that is connected to thecirculation loop formed by channels 15. To this end channels 15 may bein communication with the tank or the other source by a separate channel(not illustrated) wherein the separate channel may be selectively openedor closed so as to control or replenish the fluid supply within channels15.

Circulation of fluid within channels 15 may be controlled by a pump (notillustrated) or other similar means. Most preferably a pump ispositioned between heat exchanger 10 and molding apparatus 5 such thatthe fluid exiting the heat exchanger is pumped back into moldingapparatus 5, as illustrated by arrow A in FIG. 1. The pump may be aconventional or commercially available centrifugal pump, or the like.

The foregoing embodiment of molding apparatus 5 and channels 15 is notintended to be limiting. Rather, molding apparatus 5, to includechannels 15, may be adapted from molding apparatus previously known. Forexample, the molding apparatus portion of this invention may becomprised of any of the embodiments disclosed in U.S. Pat. Nos.3,748,866; 4,657,574; 5,398,745; 5,824,237; and 7,303,387, thedisclosures of which are incorporated by reference herein. Each of thesepatents provides a known molding apparatus with one or more channelspassing therethrough or thereabout. Accordingly, the molding apparatusand channels of this invention may be adapted as provided in thesepatents, or any similar type of molding apparatus that is known in theart and is in accordance with the teachings of this invention.

Turning to FIGS. 3A through 3C, one embodiment of heat exchanger 10 isillustrated wherein the heat exchanger is adapted to extract heat fromchannels 15. As illustrated, heat exchanger 10 may be comprised of aconventional shell-tube heat exchanger having an insulative shell 45encasing one or more channels 15. To this end, the apparatus may includeone heat exchanger 10 encasing all of channels 15. Alternatively, theremay be multiple heat exchangers in fluid communication, where each heatexchanger individually encases a single channel 15.

The heat exchanger 10 preferably utilizes convective methods to extractheat from fluid within channels 15. Most preferably, heat exchanger 10provides a second thermally conductive fluid, typically air, flowingacross the exterior surface of channels 15. The convective currentestablished by the air flow, which is preferably at ambient temperature,extracts heat from channels 15, thereby heating the fluid in the heatexchanger 10 and cooling the fluid within channels 15. The fluid flowwithin heat exchanger 10 may be either laminar or turbulent, withturbulent being preferred for the reasons discussed above. Accordingly,the heat exchanger may also include one or more fins or corrugationsoriented in one or both directions, which increase surface area and maychannel fluid flow or induce turbulence.

The shell-tube heat exchanger may be a parallel-flow heat exchanger, acounterflow heat exchanger or a cross-flow heat exchanger. Referring toFIG. 3A, the illustrated heat exchanger facilitates parallel-flow heatexchange wherein the fluid flow within the heat exchanger, as indicatedby arrow E, is parallel to the fluid flow in the channels as indicatedby arrow D. More specifically, shell 45 includes two orifices 50, 55 onopposing sides and opposing ends of shell 45. Air flows through thefirst orifice 50, through the interior of shell 45 and out of secondorifice 55. The fluids in the shell 45 and in the channels 15, while notactually mixing, are in concert with each other. To this end, as fluidin heat exchanger 10 travels along the interior of channels 15, heatfrom the fluid in channels 15 is extracted. Ultimately, this increasesthe temperature of the fluid within heat exchanger 10 and decreases thetemperature of the fluid within channels 15. Most preferably, fluidwithin channels 15 is reduced to ambient temperature and fluid withinheat exchanger 10 increases a proportionate amount such that heat isefficiently transferred from one fluid to the other.

Referring to FIG. 3B, the schematically illustrated heat exchangerfacilitates counter-flow heat exchange wherein fluid flow within theheat exchanger, as indicated by arrow F, is opposite in direction tothat of fluid flow within the channels, as indicated by arrow D. Morespecifically, shell 45 includes two orifices 50, 55 on opposing sidesand opposing ends respectively of shell 45. Air flows through secondorifice 55, through the interior of shell 45 and out of first orifice50. The respective fluids within shell 45 and channels 15, while notactually mixing, flow in parallel paths that are directly opposite ofone other. To this end, as fluid from heat exchanger 10 travels alongthe exterior sides of channels 15, heat from the fluid in the channelsis extracted. This method is preferred as it provides the most efficienttransfer of heat from the fluid within channels 15 to the fluid withinthe shell of heat exchanger 10. As with the previous embodiment, mostpreferably the temperature of the fluid within the channels is reducedto close to ambient temperature while the fluid within the heatexchanger shell increases a proportionate amount.

Referring to FIG. 3C, there is a schematically illustrated cross-flowheat exchanger wherein fluid flow within the shell of the heatexchanger, flowing in the direction indicated by arrow G, issubstantially perpendicular to the direction of fluid flow within thechannels, as indicated by arrow D. More specifically, shell 45 includesat least two orifices 50, 55 on opposing sides and may be located at anypoint along the length of shell 45. Air flows through first orifice 50,through the interior of shell 45 and out of second orifice 55. Therespective fluids in the shell 45 and in the channels 15, while notactually mixing, flow almost perpendicular to each other. To this end,as fluid from heat exchanger 10 travels along the exterior of channels15, heat from the fluid in the channels is extracted. Ultimately, thisincreases the temperature of the fluid within the heat exchanger shelland decreases the temperature of the fluid flowing within the channels.Most preferably, the temperature of fluid flowing within the channels isreduced to close to ambient temperature and the temperature of the fluidflowing within the shell of the heat exchanger increases. While FIG. 3Cillustrates two orifices 50, 50 aligned on opposing sides of the heatexchanger shell, this invention is not limited to this configuration. Inan alternative embodiment, the shell 45 may include multiple orificesaligned with one another on opposing sides of the shell 45 and along thelength of the shell such that the heat exchanger provides multiplepoints along the shell for cross-flow over channels 15. Such anembodiment would further maximize heat extraction within the heatexchanger.

This invention is not limited to the foregoing heat exchangers and maybe adapted to include any similar type of heat exchanger known in theart. Non-limiting examples of other types of heat exchangers include,but are not limited to, plate heat exchangers, regenerative heatexchangers, adiabatic wheel heat exchangers, fluid heat exchangers,dynamic scraped surface heat exchangers, phase-change heat exchangers,multi-phase heat exchangers, spiral heat exchangers, and the like.

The fluid flow rate of the heat exchanger may be regulated by any meansknown in the art. For example, the fluid flowing through shell 45 of theheat exchanger may be provided by a pump, which has not beenillustrated. Most preferably, such a pump forces ambient fluid, e.g.air, into the targeted orifice of shell 45 such that a fluid flow pathis established into and through the opposing orifice of shell 45. Whileair may be provided as one exemplary fluid, this invention is notlimited to this configuration and any fluid known in the art as beingsuitable for use in a heat exchanger may be used.

Referring to FIG. 1, heat exchanger 10 is preferably placed intocommunication with a container 65 of raw material to heat the materialprior to processing. More specifically, the heated fluid exiting heatexchanger 10, indicated by arrow H, is redirected through one or moreinsulated channels 70 into container 65. The heated fluid may be appliedto the raw material using any method known in the art. More preferably,however, the heated fluid is applied to the raw material through one ormore orifices on the underside of container 65. Most preferably, theheated fluid may be applied to the resin prior to molding at a positionsubstantially underneath the container such that the resin to be moldedis evenly heated by air, as the heated air rises within the container.Air flow from the heat exchanger forces the heated fluid into andthrough container 65. As the heated fluid passes through the container,the heat is absorbed by the raw resin material contained therein,thereby cooling the fluid. This cooled fluid is then evacuated from thecontainer into the environment or used in accordance with methodsdiscussed herein. The heat extracted from the molded product isdesirably ultimately reapplied to heat more raw material prior toprocessing into a molded product.

In an even further embodiment, as illustrated in FIG. 1, cooled fluidevacuated from container 65 is recirculated back to heat exchanger 10.In this embodiment fluid flow between heat exchanger 10 and the rawmaterial provides a second circulation loop for transfer of heat fromheat exchanger 10 to container 65 and the material therein. This secondcirculation loop is optional. Rather, the evacuated air may bereintroduced to the surrounding environment with the pump attached tothe heat exchanger resupplying ambient air in accordance with theforegoing.

The raw material(s) within container 65 may be resin or other particlesused for manufacture of plastic. To this end, the heated fluid from theheat exchanger 10 pre-heats the resin before the resin is processed.This invention, however, is not limited to this embodiment and mayinclude any raw materials known in the art for manufacturing any moldedproduct.

In an even further embodiment of this invention, a compressor or heatpump may, optionally, be added to the system at any point between theheat exchanger 10 and the raw material 65. The compressor or pump may beused to increase pressure of the heated second fluid such that it isable to flow completely through container 65 and increase effectivenessof the air flow. Most preferably, the compressor or heat pump may beplaced between the heat exchanger 10 and the container 65 at any pointalong channel 70 such that the compressor or heat pump is in fluidcommunication therewith. The compressor may be any type of compressorknown in the art such as, but not limited to, centrifugal compressors,mixed-flow compressors, axial-flow compressors, reciprocatingcompressors, rotary screw compressors, rotary vane compressors, scrollcompressors, diaphragm compressors, or the like. Similarly, the heatpump may be any heat pump that is known in the art such as, but notlimited to, compression heat pumps, absorption heat pumps, and the like.

Referring to FIG. 5, a flow chart of process aspects of the invention isillustrated. As shown, water from the heat exchanger, or alternativelyan external source, is provided and preferably pumped into the moldingapparatus by way of one or more channels. As the water passes throughthe molding apparatus, it absorbs heat from the mold, thereby increasingits temperature and cooling the temperature of the molded product. Theheated water then travels from the molding apparatus to the heatexchanger by way of one or more preferably insulated channels.

As the heated water travels into the heat exchanger, ambient air isdirected along and ultimately across the channels. As the ambient airflows along the channels it extracts heat from water in the channels,thereby cooling the water and proportionately increasing the air suchthat minimal heat is lost. The heated air is then redirected, preferablypumped, into a container housing resin to be molded. As the heated airpasses through the container, the heat is absorbed by the resin, therebypre-heating the resin and cooling the air. Accordingly, the resin isheated prior to molding using heat recaptured from later processingsteps. The cooled air may then, optionally, be recirculated back to theheat exchanger where it continues to absorb heat from the channels. Thisprocess continues until the molded product is completely cooled and/orthe resin is pre-heated to a level sufficient for processing.

This invention is advantageous because it provides cost and energyefficiencies to overall molding processes. It is estimated that theforegoing apparatus and methods may save a molded product manufacturerapproximately 1/10 to ⅕ a cent per pound of raw material, namely resin,processed. In a standard manufacturing facility, this may translate intoa savings of at least $40,000 per year. Additional advantages of thisinvention will be readily apparent to one of ordinary skill in the art.

As discussed above and from the foregoing description of the exemplaryembodiments of the invention, it will be readily apparent to thoseskilled in the art to which the invention pertains that the principlesand particularly the structures disclosed herein and the methods of usethereof can be used for applications other than those specificallymentioned. All such applications of the invention are intended to becovered by the appended claims unless expressly excluded therefrom.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics of the invention. Thedisclosed embodiments are therefore to be considered in all respects asillustrative and not restrictive, with the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced thereby.

As used in the claims herein, the term “comprising” means “including”,while the term “consisting of” means “including so much and no more”,and the term “consisting essentially of” means including the recitedelements and those minor accessories required and known to be used inthe art to facilitate the invention as claimed. The scope of theinvention is, therefore, indicated by the appended claims rather than bythe foregoing description and all changes which come within the range ofequivalency of the claims are to be considered to be embraced within thescope of the claims.

The following is claimed:
 1. Apparatus for pre-heating moldable materials prior to molding using heat recovered from the molding process comprising: a) molding apparatus having an interior surface defining a molding chamber, and at least one fluid flow channel passing through the apparatus and being thermally coupled to the molding chamber; b) a heat exchanger; c) said fluid flow channel communicating with the molding apparatus and the heat exchanger for fluid circulation between the molding apparatus and the heat exchange apparatus to transfer heat from a molded product and parts of the molding apparatus adjacent thereto within the molding apparatus to the heat exchanger; and d) a container housing raw materials for molding into a molded product the container interior being in fluid communication with the heat exchanger such that a second fluid transfers heat from the heat exchanger to the container raw material contents so as to heat the raw materials prior to molding.
 2. Apparatus of claim 1 wherein the molding apparatus and the heat exchanger are in fluid communication by way of one or more fluid channels.
 3. Apparatus of claim 2 wherein the fluid channels form a continuous loop between the molding apparatus and the heat exchanger.
 4. Apparatus of claim 1 wherein the fluid is transferred from the molding apparatus to the heat exchanger by convective currents.
 5. Apparatus of claim 1 wherein the molding apparatus is selected from the group consisting of a stretch blow-molding apparatus, injection molding apparatus, compression molding apparatus, thermomolding apparatus, thermoforming apparatus, vacuum forming apparatus, transfer molding apparatus, extrusion molding apparatus, and rotational molding apparatus.
 6. Apparatus of claim 1 where is the first fluid is selected from the group consisting of water, air, thermal oil, refrigerant, and combinations thereof.
 7. Apparatus of claim 1 wherein the first fluid is circulated between the molding apparatus and the heat exchanger using a turbulent flow.
 8. Apparatus of claim 1 wherein the heat exchanger comprises a shell-tube heat exchanger.
 9. Apparatus of claim 8 wherein the shell-tube heat exchanger is selected from the group consisting of parallel-flow heat exchangers, counterflow heat exchangers, cross-flow heat exchangers.
 10. Apparatus of claim 1 wherein the heat exchanger is selected from the group consisting of plate heat exchangers, regenerative heat exchangers, adiabatic wheel heat exchanger, fluid heat exchangers, dynamic scraped surface heat exchanger, phase-change heat exchangers, multi-phase heat exchangers and spiral heat exchangers.
 11. Apparatus of claim 1 wherein the container is in fluid communication with the heat exchanger by way of at least one fluid channel.
 12. Apparatus of claim 11 wherein at least one fluid channel extending from the heat exchanger is coupled to an orifice contained on an underside of the container.
 13. Apparatus of claim 1 wherein the second fluid is air.
 14. Apparatus of claim 1 wherein the second fluid is circulated between the heat exchanger and the container. 